Tunable Bloch surface wave constructed by two-dimensional lithium niobate grating for biosensor

Abstract

In this study, a Bloch surface wave (BSW) biosensor coupled with a two-dimensional lithium niobate grating was designed. The influence of the nonlinear characteristics of lithium niobate on the BSW sensor was theoretically investigated, and the tunability of the BSW was studied using the excitation schemes of n e and n o. To confine the energy on the surface of the solution in contact with the sensor, we introduce a distributed Bragg reflector mirror (DBR) consisting of four pairs of 76% and 42% porosity porous silicon films. A layer of lithium niobate grating is deposited on top of DBR to excite Bloch surface waves(BSW) and introduce the concept of azimuth detection in the study of the tunable properties of lithium niobate. Then, the azimuth angle of the resonance peaks excited along the n e and n o directions of lithium niobate varied by approximately 5°.